When is the best age for women to have children? Study claims to have the answers

There’s usually no shortage of reminders for women that their “biological clock is ticking.” Well, childless women feeling pestered and pressured to have kids can now add a piece of ammo to their defence arsenal.

New research out of Washington University in St. Louis says it pays to have kids later in life — literally. Speaking from a strictly financial standpoint, women who wait until they’re older than 30 tend to make more money over the course of their lifetime, according to the study.

Those who have a baby before age 25 are apparently more likely to be less well-off in the long-run.

“Children do not kill careers, but the earlier children arrive the more their mother’s income suffers. There is a clear incentive for delaying,” said study co-author Raul Santaeulalia-Llopis in a statement.

The findings are based on an analysis of nearly 1.6 million women aged 25 to 60 in Denmark. The country is often used in research because it does a great job of tracking stats.

Other key takeaways from the study include:

Women who had children before age 25 lose about two to two-and-a-half full years of annual salary during their careers.

Women who had a baby before age 28 consistently earn less throughout their careers.

Women who delay childbirth until after age 31 earn more over their entire careers than women with no children.

Those who delay having kids until age 37 add about a half year of salary to lifetime earnings.

The findings are consistent with a 2013 Global News investigation that found Ontario women — especially those from richer neighbourhoods — are waiting longer to have kids.

Of course what’s best for your finances doesn’t necessarily mean the same for your fertility and pregnancy.

Even though there’s the occasional 42-year-old who gets pregnant right away, in general, “women get pregnant easier when they’re younger,” said Dr. Al Yuzpe of the Olive Fertility Centre in Vancouver.

“And their complications are generally lower when they try to get pregnant in their mid-20s,” he said.

“But that isn’t the norm anymore.”

Almost one in five of first-time births in Canada are to women over the age of 35, Yuzpe said. Nearly one in four of all births in Canada are to women over 35.

WATCH: If you’re trying to have a baby and it’s not happening naturally, here’s what you can do

Advances in birth control options and fertility treatments have helped give women more control over their bodies, Alex McKay, research coordinator for the Sex Information and Education Council of Canada, told Global News in 2013.

“Underlying all of this is that women have gained greater and greater control over the timing of their pregnancies,” he said. “We start to see economic considerations playing an even more important role in that decision-making.”

While putting off childbirth is not always a choice, potential complications associated with it include: needing a C-section, getting gestational diabetes or pregnancy-induced hypertension, and an increased risk of genetic abnormalities. The latter is because “chromosomes become stickier so they don’t divide properly” as women age, Yuzpe explained.

Women who have held off may be comforted to know, though, that their chance of conceiving any given month only drops by five per cent (to 20 per cent) when they hit 30.

“Nobody ever has better than a 25 per cent chance [of conceiving each month], even if they’re 21,” said Yuzpe.

If you’re over the age of 37 and haven’t gotten pregnant in a year, Yuzpe said your chances of getting pregnant naturally is seven or eight per cent.

Overall, he added, 65 per cent of women should be pregnant within six months of trying.

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There are a number of options for those who are having trouble conceiving. In vitro fertilization is typically a last resort — partly because it’s so pricey. It can cost $10,000 to $12,000 for a single round, and it takes about three cycles for most women to get pregnant.

The treatment is covered in Denmark, which also offers 18-month maternity leaves. Due to those key differences, researchers argue the impact of childbirth can have an even greater financial impact on women in North America, who don’t have those luxuries.

“If children are shutting down women’s career growth and these pervasive effects vanish after the mid-30s, then we should start taking seriously the case for employer-covered fertility treatments,” said Santaeulalia-Llopis.